In a conventional engine carburetor, the theoretical air fuel ratio generally ranges about 15:1-16:1. However, the actual air fuel ratio under different load conditions is exemplified as follows:
______________________________________ LOAD Air-Fuel Ratio ______________________________________ 1. Slow Non-load running 11.8:1-12.8:1 2. Low load running 13:1-14:1 3. Medium load running 15:1-16:1 4. High load running 12.5:1-13.8:1 ______________________________________
In order to enhance the complete combustion of fuel and to reduce the pollutants such as: hydrocarbon, carbon monoxide and nitrogen oxide, due to incomplete combustion, excess air is added to the gas mixture to have an air-rich air fuel ratio ranging about 18:1-19:1.
A secondary air stream is thus added to the inlet manifold to dilute the gas mixture for saving fuel and for complete combustion, such as found in Ford (Cortina) or Honda (Civic) car. However, the secondary air conduit provided on the inlet manifold may only deliver an air stream of fixed quantity and can not variate the air quantity in response to the different gas quantity as added. Accordingly, such a secondary air system still can not provide a suitable air-fuel mixture for energy-saving purpose.
The present inventor has found the defects of a conventional car engine and invented the present air-rich fuel saver.